from __future__ import annotations
import sys
import logging

from typing import Callable, Any, List, Iterator

from .menu import Menu
from ..general import SysCommand, secret
from ..hardware import has_uefi
from ..storage import storage
from ..output import log
from ..profiles import is_desktop_profile
from ..disk import encrypted_partitions
from ..locale_helpers import set_keyboard_language
from ..user_interaction import get_password, ask_for_a_timezone
from ..user_interaction import ask_ntp
from ..user_interaction import ask_for_swap
from ..user_interaction import ask_for_bootloader
from ..user_interaction import ask_hostname
from ..user_interaction import ask_for_audio_selection
from ..user_interaction import ask_additional_packages_to_install
from ..user_interaction import ask_to_configure_network
from ..user_interaction import ask_for_superuser_account
from ..user_interaction import ask_for_additional_users
from ..user_interaction import select_language
from ..user_interaction import select_mirror_regions
from ..user_interaction import select_locale_lang
from ..user_interaction import select_locale_enc
from ..user_interaction import select_disk_layout
from ..user_interaction import select_kernel
from ..user_interaction import select_encrypted_partitions
from ..user_interaction import select_harddrives
from ..user_interaction import select_profile
from ..user_interaction import select_archinstall_language
from ..translation import Translation

class Selector:
	def __init__(
		self,
		description :str,
		func :Callable = None,
		display_func :Callable = None,
		default :Any = None,
		enabled :bool = False,
		dependencies :List = [],
		dependencies_not :List = [],
		exec_func :Callable = None,
		preview_func :Callable = None,
		mandatory :bool = False
	):
		"""
		Create a new menu selection entry

		:param description: Text that will be displayed as the menu entry
		:type description: str

		:param func: Function that is called when the menu entry is selected
		:type func: Callable

		:param display_func: After specifying a setting for a menu item it is displayed
		on the right side of the item as is; with this function one can modify the entry
		to be displayed; e.g. when specifying a password one can display **** instead
		:type display_func: Callable

		:param default: Default value for this menu entry
		:type default: Any

		:param enabled: Specify if this menu entry should be displayed
		:type enabled: bool

		:param dependencies: Specify dependencies for this menu entry; if the dependencies
		are not set yet, then this item is not displayed; e.g. disk_layout depends on selectiong
		harddrive(s) first
		:type dependencies: list

		:param dependencies_not: These are the exclusive options; the menu item will only be
		displayed if non of the entries in the list have been specified
		:type dependencies_not: list

		:param exec_func: A function with the name and the result of the selection as input parameter and which returns boolean.
		Can be used for any action deemed necessary after selection. If it returns True, exits the menu loop, if False,
		menu returns to the selection screen. If not specified it is assumed the return is False
		:type exec_func: Callable

		:param preview_func: A callable which invokws a preview screen (not implemented)
		:type preview_func: Callable

		:param mandatory: A boolean which determines that the field is mandatory, i.e. menu can not be exited if it is not set
		:type mandatory: bool
		"""

		self._description = description
		self.func = func
		self._display_func = display_func
		self._current_selection = default
		self.enabled = enabled
		self._dependencies = dependencies
		self._dependencies_not = dependencies_not
		self.exec_func = exec_func
		self.preview_func = preview_func
		self.mandatory = mandatory

	@property
	def dependencies(self) -> dict:
		return self._dependencies

	@property
	def dependencies_not(self) -> dict:
		return self._dependencies_not

	@property
	def current_selection(self):
		return self._current_selection

	def set_enabled(self, status :bool = True):
		self.enabled = status

	def update_description(self, description :str):
		self._description = description

	def menu_text(self) -> str:
		current = ''

		if self._display_func:
			current = self._display_func(self._current_selection)
		else:
			if self._current_selection is not None:
				current = str(self._current_selection)

		if current:
			padding = 35 - len(str(self._description))
			current = ' ' * padding + f'SET: {current}'

		return f'{self._description} {current}'

	@property
	def text(self):
		return self.menu_text()

	def set_current_selection(self, current :str):
		self._current_selection = current

	def has_selection(self) -> bool:
		if self._current_selection is None:
			return False
		return True

	def get_selection(self) -> Any:
		return self._current_selection

	def is_empty(self) -> bool:
		if self._current_selection is None:
			return True
		elif isinstance(self._current_selection, (str, list, dict)) and len(self._current_selection) == 0:
			return True
		return False

	def is_enabled(self) -> bool:
		return self.enabled

	def is_mandatory(self) -> bool:
		return self.mandatory

	def set_mandatory(self, status :bool = True):
		self.mandatory = status
		if status and not self.is_enabled():
			self.set_enabled(True)

class GeneralMenu:
	def __init__(self, data_store :dict = None, auto_cursor=False):
		"""
		Create a new selection menu.

		:param data_store:  Area (Dict) where the resulting data will be held. At least an entry for each option. Default area is self._data_store (not preset in the call, due to circular references
		:type  data_store:  Dict

		:param auto_cursor: Boolean which determines if the cursor stays on the first item (false) or steps each invocation of a selection entry (true)
		:type auto_cursor: bool

		"""
		self._translation = Translation.load_nationalization()
		self.is_context_mgr = False
		self._data_store = data_store if data_store is not None else {}
		self.auto_cursor = auto_cursor
		self._menu_options = {}
		self._setup_selection_menu_options()

	def __enter__(self, *args :Any, **kwargs :Any) -> GeneralMenu:
		self.is_context_mgr = True
		return self

	def __exit__(self, *args :Any, **kwargs :Any) -> None:
		# TODO: https://stackoverflow.com/questions/28157929/how-to-safely-handle-an-exception-inside-a-context-manager
		# TODO: skip processing when it comes from a planified exit
		if len(args) >= 2 and args[1]:
			log(args[1], level=logging.ERROR, fg='red')
			print("    Please submit this issue (and file) to https://github.com/archlinux/archinstall/issues")
			raise args[1]

		for key in self._menu_options:
			sel = self._menu_options[key]
			if key and key not in self._data_store:
				self._data_store[key] = sel._current_selection

		self.exit_callback()

	def _setup_selection_menu_options(self):
		""" Define the menu options.
			Menu options can be defined here in a subclass or done per progam calling self.set_option()
		"""
		return

	def pre_callback(self, selector_name):
		""" will be called before each action in the menu """
		return

	def post_callback(self, selector_name :str, value :Any):
		""" will be called after each action in the menu """
		return True

	def exit_callback(self):
		""" will be called at the end of the processing of the menu """
		return

	def synch(self, selector_name :str, omit_if_set :bool = False,omit_if_disabled :bool = False):
		""" loads menu options with data_store value """
		arg = self._data_store.get(selector_name, None)
		# don't display the menu option if it was defined already
		if arg is not None and omit_if_set:
			return

		if not self.option(selector_name).is_enabled() and omit_if_disabled:
			return

		if arg is not None:
			self._menu_options[selector_name].set_current_selection(arg)

	def enable(self, selector_name :str, omit_if_set :bool = False , mandatory :bool = False):
		""" activates menu options """
		if self._menu_options.get(selector_name, None):
			self._menu_options[selector_name].set_enabled(True)
			if mandatory:
				self._menu_options[selector_name].set_mandatory(True)
			self.synch(selector_name,omit_if_set)
		else:
			print(f'No selector found: {selector_name}')
			sys.exit(1)

	def run(self):
		""" Calls the Menu framework"""
		# we synch all the options just in case
		for item in self.list_options():
			self.synch(item)
		cursor_pos = None
		while True:
			# Before continuing, set the preferred keyboard layout/language in the current terminal.
			# 	This will just help the user with the next following questions.
			self._set_kb_language()
			enabled_menus = self._menus_to_enable()
			menu_text = [m.text for m in enabled_menus.values()]
			selection = Menu('Set/Modify the below options', menu_text, sort=False, cursor_index=cursor_pos).run()
			if selection and self.auto_cursor:
				cursor_pos = menu_text.index(selection) + 1  # before the strip otherwise fails
				if cursor_pos >= len(menu_text):
					cursor_pos = len(menu_text) - 1
				selection = selection.strip()
			if selection:
				# if this calls returns false, we exit the menu. We allow for an callback for special processing on realeasing control
				if not self._process_selection(selection):
					break
		if not self.is_context_mgr:
			self.__exit__()

	def _process_selection(self, selection :str) -> bool:
		"""  determines and executes the selection y
			Can / Should be extended to handle specific selection issues
			Returns true if the menu shall continue, False if it has ended
		"""
		# find the selected option in our option list
		option = [[k, v] for k, v in self._menu_options.items() if v.text.strip() == selection]
		if len(option) != 1:
			raise ValueError(f'Selection not found: {selection}')
		selector_name = option[0][0]
		selector = option[0][1]

		return self.exec_option(selector_name,selector)

	def exec_option(self,selector_name :str, p_selector :Selector = None) -> bool:
		""" processes the exection of a given menu entry
		- pre process callback
		- selection function
		- post process callback
		- exec action
		returns True if the loop has to continue, false if the loop can be closed
		"""
		if not p_selector:
			selector = self.option(selector_name)
		else:
			selector = p_selector

		self.pre_callback(selector_name)

		result = None
		if selector.func:
			# TODO insert code to allow selector functions with preset value
			result = selector.func()
			self._menu_options[selector_name].set_current_selection(result)
			self._data_store[selector_name] = result
		exec_ret_val = selector.exec_func(selector_name,result) if selector.exec_func else False
		self.post_callback(selector_name,result)
		if exec_ret_val and self._check_mandatory_status():
			return False
		return True
		""" old behaviour
		# we allow for a callback after we get the result
		self.post_callback(selector_name,result)
		# we have a callback, by option, to determine if we can exit the menu. Only if ALL mandatory fields are written
		if selector.exec_func:
			if selector.exec_func(result) and self._check_mandatory_status():
				return False
		"""
		return True

	def _set_kb_language(self):
		""" general for ArchInstall"""
		# Before continuing, set the preferred keyboard layout/language in the current terminal.
		# This will just help the user with the next following questions.
		if self._data_store.get('keyboard-layout', None) and len(self._data_store['keyboard-layout']):
			set_keyboard_language(self._data_store['keyboard-layout'])

	def _verify_selection_enabled(self, selection_name :str) -> bool:
		""" general """
		if selection := self._menu_options.get(selection_name, None):
			if not selection.enabled:
				return False

			if len(selection.dependencies) > 0:
				for d in selection.dependencies:
					if not self._verify_selection_enabled(d) or self._menu_options.get(d).is_empty():
						return False

			if len(selection.dependencies_not) > 0:
				for d in selection.dependencies_not:
					if not self._menu_options.get(d).is_empty():
						return False
			return True

		raise ValueError(f'No selection found: {selection_name}')

	def _menus_to_enable(self) -> dict:
		""" general """
		enabled_menus = {}

		for name, selection in self._menu_options.items():
			if self._verify_selection_enabled(name):
				enabled_menus[name] = selection

		return enabled_menus

	def option(self,name :str) -> Selector:
		# TODO check inexistent name
		return self._menu_options[name]

	def list_options(self) -> Iterator:
		""" Iterator to retrieve the enabled menu option names
		"""
		for item in self._menu_options:
			yield item

	def list_enabled_options(self) -> Iterator:
		""" Iterator to retrieve the enabled menu options at a given time.
		The results are dynamic (if between calls to the iterator some elements -still not retrieved- are (de)activated
		"""
		for item in self._menu_options:
			if item in self._menus_to_enable():
				yield item

	def set_option(self, name :str, selector :Selector):
		self._menu_options[name] = selector
		self.synch(name)

	def _check_mandatory_status(self) -> bool:
		for field in self._menu_options:
			option = self._menu_options[field]
			if option.is_mandatory() and not option.has_selection():
				return False
		return True

	def set_mandatory(self, field :str, status :bool):
		self.option(field).set_mandatory(status)

	def mandatory_overview(self) -> [int, int]:
		mandatory_fields = 0
		mandatory_waiting = 0
		for field in self._menu_options:
			option = self._menu_options[field]
			if option.is_mandatory():
				mandatory_fields += 1
				if not option.has_selection():
					mandatory_waiting += 1
		return mandatory_fields, mandatory_waiting

	def _select_archinstall_language(self, default_lang):
		language = select_archinstall_language(default_lang)
		self._translation.activate(language)
		return language


class GlobalMenu(GeneralMenu):
	def __init__(self,data_store):
		super().__init__(data_store=data_store, auto_cursor=True)

	def _setup_selection_menu_options(self):
		self._menu_options['archinstall-language'] = \
			Selector(
				_('Select Archinstall language'),
				lambda: self._select_archinstall_language('English'),
				default='English',
				enabled=True)
		self._menu_options['keyboard-layout'] = \
			Selector(_('Select keyboard layout'), lambda: select_language('us'), default='us')
		self._menu_options['mirror-region'] = \
			Selector(
				_('Select mirror region'),
				lambda: select_mirror_regions(),
				display_func=lambda x: list(x.keys()) if x else '[]',
				default={})
		self._menu_options['sys-language'] = \
			Selector(_('Select locale language'), lambda: select_locale_lang('en_US'), default='en_US')
		self._menu_options['sys-encoding'] = \
			Selector(_('Select locale encoding'), lambda: select_locale_enc('utf-8'), default='utf-8')
		self._menu_options['harddrives'] = \
			Selector(
				_('Select harddrives'),
				lambda: self._select_harddrives())
		self._menu_options['disk_layouts'] = \
			Selector(
				_('Select disk layout'),
				lambda: select_disk_layout(
					storage['arguments'].get('harddrives', []),
					storage['arguments'].get('advanced', False)
				),
				dependencies=['harddrives'])
		self._menu_options['!encryption-password'] = \
			Selector(
				_('Set encryption password'),
				lambda: self._select_encrypted_password(),
				display_func=lambda x: secret(x) if x else 'None',
				dependencies=['harddrives'])
		self._menu_options['swap'] = \
			Selector(
				_('Use swap'),
				lambda: ask_for_swap(),
				default=True)
		self._menu_options['bootloader'] = \
			Selector(
				_('Select bootloader'),
				lambda: ask_for_bootloader(storage['arguments'].get('advanced', False)),
				default="systemd-bootctl" if has_uefi() else "grub-install")
		self._menu_options['hostname'] = \
			Selector(_('Specify hostname'), lambda: ask_hostname())
		self._menu_options['!root-password'] = \
			Selector(
				_('Set root password'),
				lambda: self._set_root_password(),
				display_func=lambda x: secret(x) if x else 'None')
		self._menu_options['!superusers'] = \
			Selector(
				_('Specify superuser account'),
				lambda: self._create_superuser_account(),
				dependencies_not=['!root-password'],
				display_func=lambda x: list(x.keys()) if x else '')
		self._menu_options['!users'] = \
			Selector(
				_('Specify user account'),
				lambda: self._create_user_account(),
				default={},
				display_func=lambda x: list(x.keys()) if x else '[]')
		self._menu_options['profile'] = \
			Selector(
				_('Specify profile'),
				lambda: self._select_profile(),
				display_func=lambda x: x if x else 'None')
		self._menu_options['audio'] = \
			Selector(
				_('Select audio'),
				lambda: ask_for_audio_selection(is_desktop_profile(storage['arguments'].get('profile', None))))
		self._menu_options['kernels'] = \
			Selector(
				_('Select kernels'),
				lambda: select_kernel(),
				default=['linux'])
		self._menu_options['packages'] = \
			Selector(
				_('Additional packages to install'),
				lambda: ask_additional_packages_to_install(storage['arguments'].get('packages', None)),
				default=[])
		self._menu_options['nic'] = \
			Selector(
				_('Configure network'),
				lambda: ask_to_configure_network(),
				display_func=lambda x: x if x else _('Not configured, unavailable unless setup manually'),
				default={})
		self._menu_options['timezone'] = \
			Selector(_('Select timezone'), lambda: ask_for_a_timezone())
		self._menu_options['ntp'] = \
			Selector(
				_('Set automatic time sync (NTP)'),
				lambda: self._select_ntp(),
				default=True)
		self._menu_options['install'] = \
			Selector(
				self._install_text(),
				exec_func=lambda n,v: True if self._missing_configs() == 0 else False,
				enabled=True)

		self._menu_options['abort'] = Selector(_('Abort'), exec_func=lambda n,v:exit(1), enabled=True)

	def _update_install(self,name :str = None ,result :Any = None):
		text = self._install_text()
		self._menu_options.get('install').update_description(text)

	def post_callback(self,name :str = None ,result :Any = None):
		self._update_install(name,result)

	def exit_callback(self):
		if self._data_store.get('harddrives', None) and self._data_store.get('!encryption-password', None):
			# If no partitions was marked as encrypted, but a password was supplied and we have some disks to format..
			# Then we need to identify which partitions to encrypt. This will default to / (root).
			if len(list(encrypted_partitions(storage['arguments'].get('disk_layouts', [])))) == 0:
				storage['arguments']['disk_layouts'] = select_encrypted_partitions(
					storage['arguments']['disk_layouts'], storage['arguments']['!encryption-password'])

	def _install_text(self):
		missing = self._missing_configs()
		if missing > 0:
			return _('Install ({} config(s) missing)').format(missing)
		return 'Install'

	def _missing_configs(self):
		def check(s):
			return self._menu_options.get(s).has_selection()

		missing = 0
		if not check('bootloader'):
			missing += 1
		if not check('hostname'):
			missing += 1
		if not check('audio'):
			missing += 1
		if not check('timezone'):
			missing += 1
		if not check('!root-password') and not check('!superusers'):
			missing += 1
		if not check('harddrives'):
			missing += 1
		if check('harddrives'):
			if not self._menu_options.get('harddrives').is_empty() and not check('disk_layouts'):
				missing += 1

		return missing

	def _set_root_password(self):
		prompt = str(_('Enter root password (leave blank to disable root): '))
		password = get_password(prompt=prompt)

		# TODO: Do we really wanna wipe the !superusers and !users if root password is set?
		# What if they set a superuser first, but then decides to set a root password?
		if password is not None:
			self._menu_options.get('!superusers').set_current_selection(None)
			storage['arguments']['!users'] = {}
			storage['arguments']['!superusers'] = {}

		return password

	def _select_encrypted_password(self):
		if passwd := get_password(prompt=str(_('Enter disk encryption password (leave blank for no encryption): '))):
			return passwd
		else:
			return None

	def _select_ntp(self) -> bool:
		ntp = ask_ntp()

		value = str(ntp).lower()
		SysCommand(f'timedatectl set-ntp {value}')

		return ntp

	def _select_harddrives(self):
		old_haddrives = storage['arguments'].get('harddrives', [])
		harddrives = select_harddrives()

		# in case the harddrives got changed we have to reset the disk layout as well
		if old_haddrives != harddrives:
			self._menu_options.get('disk_layouts').set_current_selection(None)
			storage['arguments']['disk_layouts'] = {}

		if not harddrives:
			prompt = _(
				"You decided to skip harddrive selection\nand will use whatever drive-setup is mounted at {} (experimental)\n"
				"WARNING: Archinstall won't check the suitability of this setup\n"
				"Do you wish to continue?"
			).format(storage['MOUNT_POINT'])

			choice = Menu(prompt, ['yes', 'no'], default_option='yes').run()

			if choice == 'no':
				return self._select_harddrives()

		return harddrives

	def _select_profile(self):
		profile = select_profile()

		# Check the potentially selected profiles preparations to get early checks if some additional questions are needed.
		if profile and profile.has_prep_function():
			namespace = f'{profile.namespace}.py'
			with profile.load_instructions(namespace=namespace) as imported:
				if not imported._prep_function():
					log(' * Profile\'s preparation requirements was not fulfilled.', fg='red')
					exit(1)

		return profile

	def _create_superuser_account(self):
		superuser = ask_for_superuser_account(str(_('Create a required super-user with sudo privileges: ')), forced=True)
		return superuser

	def _create_user_account(self):
		users, superusers = ask_for_additional_users(str(_('Enter a username to create an additional user (leave blank to skip): ')))
		storage['arguments']['!superusers'] = {**storage['arguments'].get('!superusers', {}), **superusers}

		return users